1. Field of the Invention
The present invention relates to an exercise device and, more particularly, to a treadmill exercise device having a better structural strength and an adjusting device which is easily to be operated to adjust a tensile force of the belt.
2. Brief Description of the Prior Art
A conventional treadmill exercise device includes two side frames between which two rollers are separately and rotatably disposed, an endless belt wrapped around the two rollers so that a user can run on the belt. In order to support the user's weight during using the treadmill exercise device, a board is inserted between the two side frames and the belt. However, a certain thickness and stiffness of the board are required so as to sufficiently support the user's weight. The board increases a total weight of the treadmill exercise device.
The present invention intends to provide an improved treadmill exercise device to mitigate and/or obviate the above-mentioned problems.